Milkey argued the landmark case, on behalf of 12 states, in front of the U.S. Supreme Court.

During the April presentation, he reflected on the value of using the law as a tool for driving social change and urged the law students present to use their skills to help fashion a better world for all.

Around the year 2000, as chief of the environmental protection division of the state's Attorney General's office, James Milkey was trying to do just that.

The George W. Bush administration had walked away from its campaign promise to address carbon dioxide emissions, and under Bush, the EPA had declined to regulate those emissions.

Milkey was considering a couple of legal options to deal with the critical problem of carbon emissions.

One possibility was to file nuisance law suits against emitters to see if that could force change. A second possibility was to have the states sue the EPA to force them to do their job.

No state had ever filed this type of suit before—and it wasn’t clear if the states even had a legal right to do so. Milkey decided this approach had a better chance of success.

Once the case was brought, a lower court ruling issued a three-way split decision in which the judges couldn’t even decide whether the states had a right to sue. That left Milkey with a feeling that his strategy had failed.

Despite the lack of a clear decision from the lower court, the Supreme Court chose to hear the case anyway, so Milkey headed to Washington.

The case mostly hinged around the Clean Air Act and whether or not carbon dioxide was a pollutant that the EPA must regulate. But the issue of “standing" remained equally important.

The Supreme Court could have dodged a difficult question related to CO2 emissions by deciding, on a technicality, that the states didn’t have a right to sue.

The proceedings were not without their humorous moments, Milkey recalled.

At one point, the late Justice Antonin Scalia confused the troposphere with the stratosphere, causing Milkey to correct him: “Respectfully, Your Honor, it is not the stratosphere; it’s the troposphere.”

“Troposphere, whatever; I told you before I'm not a scientist," Scalia responded. "That's why I don't want to deal with global warming.”